Mustang Brake System Buyer's Guide - Stop It...Now! - Part 2

Putting a Quick Stop to Your Favorite Steed Has Never Been Easier

October 2, 2009

In part one of our brake buyer's guide last month, we introduced you to a wide variety of companies that specialize in upgrading the braking system of your Mustang or Ford. This month we complete the story with another great batch of companies that offer everything from mild to wild. As enthusiasts whose formative years included the dark ages that considered a Lincoln Versailles rear disc upgrade as the cat's meow, we're grateful for the variety of products these companies represent. Dig in, eat it up, and revel in the performance paradise we've grown to take for granted of late. It hasn't always been this way!!

Bigger Is Better?
Prevailing wisdom follows the bigger is better axiom, but we dug a bit deeper into the subject by discussing brake theory with James Walker, Jr., author of SA Design's High-Performance Brake Systems. Beyond currently serving as a consulting engineer for StopTech, Walker heads up scR motorsports, and in the past 15 years has been employed in brake system design, development, and application engineering at Kelsey Hayes, Delphi, Bosch, GM, and Ford Motor Company. Yep, needless to say Walker's knowledge of the subject far surpasses our own, and we appreciate him sharing his thoughts.

Walker outlined what he feels to be the three most pertinent reasons for considering bigger brakes than the factory provided, 1) improved heat absorption and dissipation--with a corresponding improvement in fade resistance, 2) improved rigidity/reduced compliance through braided lines and stiffer calipers (resulting in a firmer, more responsive brake pedal), and 3) improved curb appeal. Walker's list is clearly in order of importance from the racer or open tracker's perspective, as keeping brakes within target temperatures is paramount to effectiveness, consistency, and a competitive edge. Bling is last on the list for the hard-core enthusiast, and yet we recognize that many brake systems are bought with aesthetics as a primary motivator--no judgment here, just an observation.

The role of the tire is frequently overlooked in the quest for improved brake performance, but Walker's book devotes a whole chapter to the subject. The ability of the tire to provide enough traction prior to lockup is arguably the biggest factor in the overall scheme of things, because as Walker proclaims from atop his soapbox, "The tire stops the car." Exceed the tire's traction capacity, and any extra braking power becomes totally useless. As Walker puts it, "If you have enough torque to lock up your brakes, you have all the torque you need." Oversimplified? Sure, because most, if not all factory systems will do this if pushed hard enough--at least until they get hot from repetitive use, which brings us right back to Walker's number one reason for considering the bigger brakes--heat absorption and dissipation.

In the end, you want to determine the equipment which is necessary to achieve your performance goals, rather than going overboard with the biggest combination possible. Bigger really isn't always better, for "bigger" almost always equates to "heavier." Weight is an enemy in virtually all performance applications, all the more when it is unsprung and rotating, increasing inertia forces. In short, the reality is that obtaining adequate and repeated brake torque with the smallest (read lightest) equipment that will do the job, is optimal.

Conspicuously absent from Walker's short list is reduced braking distances--what many would presume to be a given byproduct of bigger brakes. Not so says Walker, returning to his point that having enough brake torque to lock the tires is indicative that the chassis already has maximum usable torque--though not necessarily enough thermal capacity for extreme duty conditions. If tire parameters remain the same before and after a brake upgrade, stopping distance changes are unlikely with one caveat: the increased thermal capacity of the bigger brakes should enable your stopping distances to remain constant due to good heat dissipation, rather than increasing due to brake fade.

When pairing wider/stickier tires with more powerful brakes, decreased distances may be possible, but there is another factor to consider--driver comfort. As Walker explained, "If it takes, say, 50 pounds of driver leg force on the brake pedal to get typical stock tires to lock with stock brakes, it will probably require 80 to 100 pounds of brake pedal force to get good race tires to lock with the same brakes." While this means the stock brake system most likely can still generate the maximum usable brake torque, such extra physical effort will likely result in driver fatigue. In this case, changing the leverage in the system, i.e. through a larger rotor/caliper combination, could be worthwhile simply for reducing driver effort. Other reasons to consider an alternative braking system, particularly on a vintage vehicle, could include improved serviceability, lighter weight components, and broader selection of brake pad compounds.

We learned much from a few minutes of conversation with Walker--far too much to share in such minimal space. We look forward to a thorough read of his book, and suspect many of our readers would find it of considerable interest as well.

Aerospace Components
This St. Petersburg, Florida, based company got its start as a government contractor, primarily in defense systems and space station components--hence the logical name. Long known as a major player in the hard-core drag racing world, we were surprised to learn that Aerospace now sells as many of its street-friendly Pro Street brake systems as its drag-race-specific items, and offers both for virtually every generation of Mustang.

Aerospace is proud to say that nearly all its brake components are manufactured in house, which, in addition to its standard product line, means the company can offer custom applications as well. Even road race brake systems are available, though the drag and street product lines are the dominant sellers.

Beyond brake kits, Aerospace's racy product line includes items such as vacuum pumps, battery and nitrous bottle mounting kits, cooling and fuel system components, and much more.

Differing Demands
Reflecting a near constant in life, when it comes to brake systems, there is clearly no "one size fits all" solution. The unique demands of specific vehicle genres means optimal performance will come from a product uniquely designed for the application, and perhaps nowhere is this more evident in the contrast between drag race and road race brakes.

One common thread between these two sports is the minimizing of weight. Thusly the use of lightweight materials, such as aluminum calipers and rotor hats, is the norm. For drag applications, manufacturers often offer guidance for the suitability of their product based on vehicle weight. For example, Wilwood's DPS Front Drag Race kits offers what would be laughable to any road racer, but is perhaps the perfect setup for drag racers with a car of no more than 2,400 lbs. This kit features minimalist 10x0.32-inch drilled solid rotors and lightweight two-piston billet calipers, which, if apropos for your dedicated race car, claims an average weight reduction of 35 pounds over the stock equipment. A bit heavier than the DPS setup, but appropriate for heavier cars, is Wilwood's DPR drag race brakes with four-piston calipers, and either 11.75x0.35-inch solid rotors, or 11.75x0.81 vented rotors depending on application. To be sure, there are factors to consider beyond weight, i.e. top speed of the vehicle, rear brake componentry, parachutes, and so on, but weight is surely a primary consideration when choosing the right brakes for your ride--drag race or otherwise.

Contrast the Wilwood drag kits to Griggs Racing's 4 on 4 road race kit, with beefy vented rotors measuring 13.5x1.25 inches, and NASCAR derived four-piston aluminum calipers. This comparison provides a glimpse to the vastly different demands and design priorities between drag and road racing equipment, and hints at the compromises which have to be made when building an "all around" performer.

Stainless Steel Brakes Corporation
Variety may well be the spice of life at SSBC, for the company that pioneered stainless steel sleeving of classic Corvette and Mustang calipers back in 1975, indeed has one of the broadest brake lineups in the industry.

Kits are available for a dizzying array of vehicles, including virtually all eras of Mustangs and popular classic Fords. From factory style single- and multiple-piston iron calipers, to modern billet aluminum calipers in a variety of configurations, SSBC will have something for everyone--including 14-inch/eight-piston "V8" front kits for the S197.

Hydraulically Speaking
Whether buying a "brake kit," or acquiring a parts list for a brake upgrade of your own, several important ancillary items will be required. Flexible brake lines are a part of some kits, but if they're not, we strongly advise upgrading to stainless steel braided lines which are available from a variety of specialists. Frankly, braided lines are considered one of the basics, and should be considered even on cars delivered with an otherwise competent factory braking system, i.e. '94-'04 Cobra Mustangs. While these lines' primary role is to provide improved abrasion resistance, a significant secondary benefit is their resistance to expansion under hydraulic pressure, resulting in a more consistent and responsive brake pedal.

Almost never included in a brake kit is the most basic item which makes a brake system function, the fluid. Brake fluid is classified by U.S. Department of Transportation standards, including DOT 3, DOT 4, DOT 5, and DOT 5.1 varieties. Of great concern for performance enthusiasts, is the boiling point of each fluid. This is important since boiling fluid during hard brake use will cause a spongy pedal, and reduced effectiveness. The following is a breakdown of the DOT boiling points for the different brake fluids--actually the minimum temperatures for a fluid to qualify. Racing fluids often have boiling points that are far higher than the minimum number to achieve the rating, in fact sometimes as high as 550-600 degrees Fahrenheit. It should be noted that these particular numbers are for dry boiling points, in other words, fresh fluid that hasn't absorbed any moisture:

DOT 3

DOT 4

DOT 5

DOT 5.1

401° F

446° F

509° F

509° F

So what's the difference between DOT 5, and DOT 5.1? The chemical composition of the fluid; brake fluids are usually glycol based, with the exception of the silicone based DOT 5. Since glycol is corrosive to paint while silicone is not, in some instances a DOT 5 may be appealing to the restoration crowd. The downside to DOT 5 fluids, and it's a big one, is the inherently spongy brake pedal that results. Consequently, DOT 5 should never be considered for any type of performance application despite the relatively high boiling point; rather, a DOT 3, DOT 4, or DOT 5.1 fluid should be used--dictated of course by how much abuse you and your vehicle can heap on. It should also be noted that glycol and silicone based brake fluids must not be mixed. If switching from one type of fluid to another, a complete brake system flush must be accomplished.

Steeda Autosports
Yet another big name in late-model Mustang performance, Steeda has plenty of appealing brake upgrades amongst its all encompassing product line, including those from many aftermarket brake manufacturers. With '05 and newer models being the hot commodity nowadays, the company has focused its Steeda brand-name specifically on the S197 cars, with a sweet 14-inch/four-piston upgrade that had special attention paid to compatibility with the S197's sensitive ABS system. Also popular is a cost effective ($499.95) upgrade kit for the rear, increasing rotor size from a stock S197 11.8-inches, to a full 13-inches with your choice of slotted or cross-drilled discs.

Enthusiasts with '94-'04s need not lament, as Steeda is big on a couple of Brembo upgrades for this earlier chassis. A 13-inch four-piston kit is popular due to price ($1,449) and the ability to fit a wide variety of 17-inch wheels, while a 14-inch four-piston kit is likely more the domain of serious track hounds.

Stillen
Steve Millen's company may be a relative newcomer to the Mustang market, but it's sure no Johnny come lately. Formed in 1986, Stillen has long been known as a Nissan tuner extraordinaire, but more recently has parlayed its sports car expertise to a wider variety of vehicle makes--including late model Mustangs and Ford GTs.

Stillen takes a different route to improved braking, using highly rated components from AP Racing. While not a household name in Mustang circles, AP is a top name in international motorsports, and the Stillen kits offer both four- and six-piston caliper configurations.

Stoptech
If it's tremendous stopping power you want, you'll get it with Stoptech's "Big Brake Kits" for Mustangs from '79-'09. Carefully engineered to maintain a balanced brake system, Stoptech calipers use different piston sizes within the same caliper family depending on the vehicle and rotor size of the application.

Fox Mustangs must use a SN-95 spindle to take advantage of Stoptech brakes, but then the offerings are much the same as the '94-'04s, meaning two front kits featuring the ST-40 four-piston caliper. Both 13- and 14-inch two-piece rotors are offered for this application, with caliper pistons sized for optimal brake torque. Stoptech S197 systems are offered with either four-piston or six-piston calipers--the latter with as much as a 15-inch rotor.

Street Or Track, LLC
We always enjoy running across enthusiasts who have parlayed their interest in Mustangs into a successful business. Such is the case with Shaun Burgess, who founded Street or Track in 2003 with the debut of his adjustable strut rods for early Mustangs. Since then, more products have followed, including pertinent braking systems for '65-'73 Mustangs and similar classic Fords. Like several others, Street or Track has structured its brake products around readily available and effective '94-'04 Cobra Mustang calipers, while specific engineering has created a unique product line that could be just the ticket for your particular application.

Perhaps the biggest appeal to Street or Track brakes is the ability to run either SN-95 or vintage style 17-inch or larger wheels in conjunction with Cobra brakes--without using wheel spacers. Period-looking rims such as the popular Torque Thrust II require spacers when using a stock Cobra rotor due to the shallow hat offset of the SN-95 disc. Street or Track solved this dilemma by offering rotors with a deeper, more traditional hat offset, proving a logical choice for many enthusiasts. On the other hand, if you want to use SN-95 spec wheels for an updated look, specific brackets for this arrangement are available as well, and use the standard Cobra 13-inch rotor.

Traditionalists who want to stay with 15-inch wheels should take heart. Front and rear kits are available for those wishing to combine Cobra brakes with 15-inch wheels, making use of smaller 11.25/10.5-inch rotor sizes.

Vintage Venom
Vintage Venom is a company that has latched on to the appeal of pairing modern OEM brakes/wheels with a classic chassis, and done something about it. With a myriad of packages to help put SN-95 Cobra discs on the front, back, or both ends of the '65-'73 Mustang and other closely related sibs, the customer need only decide how much of the Cobra brakes they want to procure themselves. Vintage Venom can supply anything from basic adapter kits, to the whole enchilada. A minimum of 17-inch wheels are necessary to accomplish the swap (15-inch for the rear), which is specifically designed to locate a SN-95 spec 8-inch wide rim perfectly between the control arm and the fender lip.

Bucking the "vintage" portion of the company name, a more recent addition to its product lineup is a hardware kit that adapts S197 GT500 front brakes to '94-'04 Mustangs. Designed to use a GT500 18x9.5-inch rim, or equivalent, at all four corners, track testing on Vintage Venom's '03 Mach 1 has demonstrated an impressive 50 percent reduction in brake temps when compared to the stock Cobra-spec binders.

Wilwood
Both old timers and newcomers will be familiar with the name Wilwood, as the company has been a mainstay in the high performance brake industry for more than 30 years. Offering everything from featherweight drag racing systems to hard-core road race products, Wilwood disc brakes are available for both classic and late-model Mustangs--either in package form, or as individual components for custom applications.

It's worthwhile to point out that Wilwood is more than a brake manufacturer, for they build a variety of other race car components to include clutch slave cylinders, quick release steering hubs, brake/clutch pedal assemblies, Mustang II architecture spindles, and more. The Wilwood brake lineup casts a wide net for classic and late-model Mustangs, and includes a variety of rotors and calipers--Dynalite (billet four-piston), Dynapro 4 and 6 (billet four- or six-piston), Superlite (billet six-piston) and monstrous W6A (forged six-piston) calipers.